Patent GB-578975-A (GB)
Title: Improvements relating to vehicle suspensions
IPC: B64C25/00
Filed: 1944-05-25
Abstract: 578,975. Vehicle spring-suspensions. GREAVES, R. May 25, 1944, Nos. 10129, 18240 and 21226. [Classes 108 (ii) and 108 (iii)] [Also in Group XXXIII] A suspension means between a supporting wheel and a vehicle or aircraft chassis frame or body, includes a shackle pivotally connected at spaced points to arms or links which extend in opposite directions from the shackle and are pivotally connected to the chassis frame, means interconnecting the shackle, or one of the arms, and the wheel-hub assembly, and prestressed resilient means connected between the shackle and the chassis frame and arranged to become progressively further stressed, to an increasing extent, as the chassis frame falls further relatively to the wheel, the resilient means being stressed to a minimum when the wheel is suspended freely, in which conditions the arms and the line of pull of the resilient means are substantially parallel to one another. As shown diagrammatically in Figs. 1, 2, the ends of the front and rear axles 21, 22 are each connected by a link C to the chassis frame at 25 and to a shackle A at 26, the shackle being further connected by a link B to the frame. The link C is stressed permanently under tension by means of a third link D connected at one end to the shackle A and at the other end to one end of a leaf-spring 27 or 33 which is pivotally connected at 28 or 32 to a bracket 29 on a bar 30 suspended from the chassis frame by links 31. Movement of the wheel from the no-load to the normalload position is greater than the spring movement, but with wheel movement from normalload to extreme-load position the corresponding spring movement is materially increased and may be greater than the wheel movement. In a modification, the links C, D are arranged more closely parallel to one another. The degree of pre-stressing of each spring 27 or 33 may be adjusted by packing the spring anchorage with plates 34 or by interconnecting bell-crank levers pivoted one at each end of the spring by a lengthwise-adjustable tension rod. Alternatively, the springs may be independently mounted and hinged centrally to a bellcrank lever pivoted by one arm directly to the chassis frame and by the other arm through an adjustable link to the frame. In another construction, Fig. 4, a longitudinal leaf-spring C<2> serves as a torque stay, tension being applied thereto through a second shackle 37 connected at its upper end to the shackle A<2>, at its lower end to the tension-applying means 38, and intermediate its ends to the chassis frame by a link 39, Instead of a transverse leaf-spring, tension may be applied by a coiled tension or compression spring or any pressure-responsive device such as a diaphragm chamber, piston- and-cylinder, or, as shown in Fig. 8, by a bellows 42 to which fluid under pressure is supplied through a pipe 48. One end of the bellows 42 and the adjacent end of the stay C are fixed to the chassis frame at 43 while the other end of the bellows is pivotally connected to the forked end 45 of the tension link D. the pivot 44 being connected by an arm 46 pivoted at 47 on the frame. Preferably, the pipes 48 of the bellows of all the wheel suspensions are connected to a common reservoir the fluid pressure of which is initially increased until roll is substantially eliminated, after which it is slightly reduced. In a further construction applied to an independent wheel suspension, Fig. 10, the bracket 67, on which the wheel-hub assembly is swivelled for steering, is connected to the chassis frame by upper and lower wishbone linkages 69, 70, the lower linkage being connected by a link 71 to the lower end of the shackle A which in turn is connected by the links B, C to the frame and by the tension link D to a bellows device 42. In another construction the invention is shown applied to a half-axle wheel suspension. The application of the invention to aircraft landing wheels is also shown (see Group XXXIII).